As an image sensing apparatus capable of sensing images and recording them on a recording medium, an electronic camera is generally known and has already been available on the market, which uses, as a recording medium, a memory card having a sold-state memory device, and can record/play back still images and moving images sensed by using a solid-state image sensing device such as a CCD or CMOS.
In general, when image sensing is performed by using a solid-state image sensing device such as a CCD or CMOS, a two-dimensional dark fixed pattern noise in the image data, obtained by the actual photographing operation while the image sensing device is in an exposed state, is corrected by using the correction value generated from the dark image data obtained by dark image photographing operation while the image sensing device is in an unexposed state. This makes it possible to suppress a deterioration in image quality due to two-dimensional fixed pattern noise such as pixel loss caused by dark current noise in the image sensing device and a fine flaw unique to the image sensing device.
The causes of a deterioration in image quality are not, however, limited to the above two-dimensional dark fixed pattern noise, and include one-dimensional dark fixed pattern noise (i.e., circuit-based noise), caused by voltage irregularity due to a resistive component in the power line in the sensor, device variations, and the like.
The above two-dimensional dark fixed pattern noise, in particular, is caused by the dark current generated when the electric charge storage time is long or the temperature of the image sensing device is high, and becomes a dominant factor for a deterioration in image quality. In contrast to this, one-dimensional dark fixed pattern noise becomes a dominant factor for a deterioration in image quality when the electric charge storage time is short or the temperature of the image sensing device is room temperature or lower. If correction data is created under the same conditions at the time of photographing operation in spite of the fact that the characteristics change depending on the settings in the image sensing apparatus, ambient temperature, and the like at the time of photographing operation, the time taken for the creation of the correction data becomes a release time lag or the like. This causes discomfort, and the user may miss a shutter chance.